The Keysight (Agilent) 81640A is a Tunable Laser Source module designed for the 8164A and 8164B mainframes. Covering both the C- and L-bands from 1510 nm to 1640 nm, it is engineered for testing critical DWDM passive components. Key features include continuous sweep, low source spontaneous emission (SSE) output for high dynamic range measurements, and mode-hop free tuning over its entire wavelength range.
Specifications
General
| Parameter | Value |
|---|---|
| Interfaces | Via mainframe backplane (GPIB, LAN, RS-232 on mainframe) |
| Display | None (uses mainframe display) |
Physical
| Parameter | Value |
|---|---|
| Power Supply | Provided via mainframe backplane |
| Operating Temperature | +10 °C to +35 °C |
| Dimensions (W×H×D) | 325 mm × 75 mm × 235 mm |
| Weight | 4.5 kg |
Optical Specifications
| Parameter | Value |
|---|---|
| Wavelength Range | 1510 nm to 1640 nm |
| Wavelength Resolution | 0.1 pm (12.5 MHz at 1550 nm) |
| Absolute Wavelength Accuracy | ±15 pm (at constant temperature) |
| Relative Wavelength Accuracy | ±5 pm |
| Wavelength Repeatability | ±1 pm (typical ±0.5 pm) |
| Wavelength Stability | ±1 pm (over 24 hours at constant temperature) |
| Tuning Speed (Continuous Sweep) | up to 40 nm/s |
| Max. Output Power (High Power Port) | >= +4 dBm (1510 nm to 1620 nm) |
| Max. Output Power (Low SSE Port) | >= 0 dBm (1510 nm to 1620 nm) |
| Power Resolution | 0.01 dB |
| Power Flatness vs. Wavelength | ±0.2 dB (typical ±0.1 dB) |
| Power Repeatability | ±0.03 dB |
| Power Stability (1 Hour) | ±0.01 dB (at constant temperature) |
| Power Stability (24 Hours) | ±0.03 dB |
| Power Linearity | ±0.05 dB |
| Spectral Linewidth (Coherence Control Off) | < 100 kHz (typical < 50 kHz) |
| Side Mode Suppression Ratio (SMSR) | >= 45 dB (typical 50 dB) |
| Signal-to-Source Spontaneous Emission (SSE) Ratio (High Power Port) | >= 55 dB/nm (1520 nm to 1620 nm) |
| Signal-to-Source Spontaneous Emission (SSE) Ratio (Low SSE Port) | >= 80 dB/nm (1520 nm to 1620 nm) |
Polarization & Connectivity
| Parameter | Value |
|---|---|
| Number of Optical Outputs | 2 (Output 1: High Power, Output 2: Low SSE) |
| Output Fiber Type | Polarization Maintaining Fiber (PMF), Panda-type |
| Polarization Extinction Ratio (PER) | >= 18 dB |
| Polarization Alignment | Key aligned to slow axis |
| Connector Interface Options | Option 071 (PMF, straight contact), Option 072 (PMF, angled contact) |
Modulation & Control
| Parameter | Value |
|---|---|
| External Digital Modulation Frequency | 300 Hz to 1 MHz |
| External Analog Modulation Frequency | 300 Hz to 1 MHz |
| Internal Modulation Duty Cycle | 50% (square wave) |
Mainframe Compatibility
| Parameter | Value |
|---|---|
| Compatible Mainframes | Keysight / Agilent 8164A, 8164B |
| Number of Slots Required | 1 bottom slot (occupies both module widths in bottom bay) |
Environmental & Standards
| Parameter | Value |
|---|---|
| Storage Temperature Range | -40 °C to +70 °C |
| Warm-up Time | 1 hour |
| Laser Safety Class | Class 3B (IEC 60825-1) / Class IIIb (FDA 21 CFR 1040.10) |
Power
| Parameter | Value |
|---|---|
| Absolute Power Accuracy | ±0.5 dB (at calibration conditions) |
| Power Range (High Power Port) | -11 dBm to +6 dBm (1520 nm to 1620 nm) |
| Power Range (Low SSE Port) | -15 dBm to +2 dBm (1520 nm to 1620 nm) |
| Dynamic Power Flatness | ±0.2 dB @ 10 nm/s (typical), ±0.5 dB @ 40 nm/s (typical) |
Wavelength
| Parameter | Value |
|---|---|
| Internal Wavelength Reference | Built-in gas cell for real-time calibration |
| Sweep Modes | Continuous sweep, Step sweep |
| Wavelength Tuning Time | < 350 ms (for 1 nm step, typical) |
| Dynamic Wavelength Accuracy | +/-10 pm (at 10 nm/s continuous sweep, typical) |
Optical Output
| Parameter | Value |
|---|---|
| Optical Return Loss | typically > 55 dB |
Signal Quality
| Parameter | Value |
|---|---|
| Relative Intensity Noise (RIN) | <-145 dB/Hz (typical, at 10 MHz to 6 GHz) |
Technology
Tunable External Cavity Diode Laser (ECDL)
Applications
DWDM passive component testing, optical amplifier testing, and spectral characterization